TEM/EDXS studies of phase separation in block and graft copolymers
| dc.contributor.author | York, Greg Allen | en |
| dc.contributor.department | Materials Engineering | en |
| dc.date.accessioned | 2017-11-09T20:41:50Z | en |
| dc.date.available | 2017-11-09T20:41:50Z | en |
| dc.date.issued | 1987 | en |
| dc.description.abstract | The relationships between molecular parameters and microdomain formation of a variety of block- and graft-copolymers were studied by Transmission Electron Microscopy (TEM). Molecular variables included chemical composition: dimethyl-, fluoropropyl and diphenyl-siloxane , sulfone styrene, paramethylstyrene, t-butylstyrene, arylester and methyl methacrylate, as well as molecular weight and distribution. Effects of the kinetics of phase-separation were also determined . Thick (approximately lmm) films cast from solvent showed more complete phase separation than either thin (about 10nm) cast films or compression-molded specimens. Spherical domains formed in alternating poly(ester/siloxanes), and phase mixing seemed to correlate with the solubility parameters of the three siloxane types. Shear-stresses during molding changed domain shapes and eliminated short-range ordering. In the PMMA-graft-dimethyl siloxane system, SK, 10K and 20K <M<sub>n</sub>> siloxanes were incorporated at 16% and 45% by weight. At 16%, spherical siloxane domains formed in both thick- and thin-cast films. The domain sizes and interdomain distances scaled with siloxane molecular weight and total block molecular weight respectively to a 2/3 power law in excellent agreement with theoretical predictions for di- and triblock copolymers. Thin films cast from the 45% siloxane graft copolymers also showed spherical domains with sizes dependent on molecular weight. However, the thick films showed phase transitions from disordered bicontinuous (M<sub>n</sub> = 5K) to lamellar (M<sub>n</sub> = 10K) to cylindrical <M<sub>n</sub> = 20K). Qualitative TEM/EDX analysis of other systems was used to identify oligomers, homopolymers, and contaminants, thus monitoring the effects of novel reaction conditions and work-up procedures. | en |
| dc.description.degree | Master of Science | en |
| dc.format.extent | xii, 181 leaves | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.uri | http://hdl.handle.net/10919/80085 | en |
| dc.language.iso | en_US | en |
| dc.publisher | Virginia Polytechnic Institute and State University | en |
| dc.relation.isformatof | OCLC# 16813119 | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject.lcc | LD5655.V855 1987.Y67 | en |
| dc.subject.lcsh | Electron microscopy | en |
| dc.subject.lcsh | Polymers | en |
| dc.title | TEM/EDXS studies of phase separation in block and graft copolymers | en |
| dc.type | Thesis | en |
| dc.type.dcmitype | Text | en |
| thesis.degree.discipline | Materials Engineering | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | masters | en |
| thesis.degree.name | Master of Science | en |
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